TY - JOUR
TI - Stress softening of multigraft copolymers
AU - R. Schlegel
AU - D. Wilkin
AU - Y. Duan
AU - R. Weidisch
AU - G. Heinrich
AU - D. Uhrig
AU - J.W. Mays
AU - H. Iatrou
AU - N. Hadjichristidis
JO - Polym. Chem.
PY - 2009
VL - 50
TODO - 26
SP - 6297--6304
PB - ELSEVIER BV
SN - null
TODO - 10.1016/j.polymer.2009.10.026
TODO - Hysteresis, Hysteresis behaviour;  Micro-domains;  Molecular architecture;  Multigraft copolymers;  Physical cross-links;  Rubber elasticity;  Spherical morphologies;  Stress softening, Architecture, elasticity;  graft copolymer;  natural polyisoprene;  polystyrene;  stress;  synthetic rubber
TODO - The hysteresis behaviour of multigraft (MG) copolymers, with a polyisoprene backbone and polystyrene (PS) side chains, was investigated by applying a modified softening model proposed by Elías-Zúñiga, which uses an approach of Ogden and Roxburgh. The model was combined with the non-affine tube model of rubber elasticity of Kaliske and Heinrich. Four parameters are obtained: chemical and physical cross-link moduli (Gc, Ge), the number of statistical segments between two successive entanglements (ne/Te) and a softening parameter (b). The model was proven to be valid by a comparison with other methods evaluating hysteresis behaviour. The characterization of the multigraft copolymers revealed a branch point and molecular architecture dependence of the softening parameter. b was low for tetrafunctional MG copolymers with cylindrical microdomains, and it was further reduced for a spherical morphology and for more complex molecular architectures. The magnitude of b also depends on the PS arm molecular weight for hexa- and tetrafunctional multigraft copolymers. © 2009 Elsevier Ltd. All rights reserved.
ER -